Oldham Lucy, Arnott Gareth, Camerlink Irene, Doeschl-Wilson Andrea, Farish Marianne, Wemelsfelder Francoise, Turner Simon P
Animal Behaviour & Welfare, Animal and Veterinary Sciences Department, Scotland's Rural College (SRUC), West Mains Rd, Edinburgh EH9 3JG, UK.
Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 7BL, UK.
Appl Anim Behav Sci. 2021 Nov;244:105488. doi: 10.1016/j.applanim.2021.105488.
Aggression between unfamiliar commercial pigs is common and likely invokes strong emotions in contestants. Furthermore, contest outcomes affect subsequent aggressive behaviour, suggesting a potential lasting influence on affective state. Here we used a combination of qualitative and quantitative methods to assess the emotional expression of pigs in agonistic encounters. We investigated how recent victory or defeat influences emotions expressed in a subsequent contest, and the role of aggressiveness as a personality trait in emotional expression. We observed the pre-escalation contest behaviour (second contest; age 13 wks) in animals of different aggressiveness (categorised using two resident intruder tests as Agg+ or Agg-, age 9 wks), which had recently won or lost a contest (first contest; 10 wks). We measured gaze direction and ear position. Observers watched video clips of the initial 30 s of the second contest and evaluated the emotional expression of 57 pigs (25 contest 1 winners, 32 contest 1 losers) using qualitative behavioural assessment (QBA) with a fixed list of 20 descriptive terms. QBA identified three principal components (PCs), accounting for 68% of the variation: PC1 (agitated/tense to relaxed/content), PC2 (fearful/aimless to confident/enjoying) and PC3 (listless/ indifferent). Agg- pigs and males showed a more positive emotionality (PC2). PC1 and PC3 were unaffected by first contest outcome and aggressiveness. Agg+ pigs were more likely to hold their ears back (X =7.8, p = 0.005) during the early contest period. Differences in attention were detected in the contest outcome × aggressiveness interaction (χ4.3, p = 0.04), whereby approaching the opponent was influenced by winning and losing in the Agg- pigs only. QBA and gaze behaviour reveal differences in emotional valence between pigs of different aggressiveness: less aggressive pigs may be more susceptible to the emotional impact of victory and defeat but overall, more aggressive pigs express more negative emotionality at the start of agonistic encounters.
陌生的商业猪之间发生攻击行为很常见，这可能会引起参赛者强烈的情绪反应。此外，比赛结果会影响随后的攻击行为，这表明对情绪状态可能有潜在的持久影响。在这里，我们使用定性和定量方法相结合的方式来评估猪在争斗遭遇中的情绪表达。我们研究了近期的胜利或失败如何影响在随后的比赛中表达的情绪，以及攻击性作为一种个性特征在情绪表达中的作用。我们观察了不同攻击性的动物（在9周龄时使用两次定居者-入侵者测试分为Agg+或Agg-）在预升级比赛行为（第二次比赛；13周龄）中的表现，这些动物最近在一场比赛（第一次比赛；10周龄）中获胜或失败。我们测量了注视方向和耳朵位置。观察者观看了第二次比赛最初30秒的视频片段，并使用具有20个描述性术语的固定列表的定性行为评估（QBA）对57头猪（25头第一次比赛获胜者，32头第一次比赛失败者）的情绪表达进行了评估。QBA确定了三个主要成分（PCs），占变异的68%：PC1（激动/紧张到放松/满足），PC2（恐惧/无目的到自信/享受）和PC3（无精打采/冷漠）。Agg-猪和雄性表现出更积极的情绪（PC2）。PC1和PC3不受第一次比赛结果和攻击性的影响。Agg+猪在比赛早期更有可能将耳朵向后贴（X =7.8，p =0.005）。在比赛结果×攻击性相互作用中检测到注意力差异（χ4.3，p =0.04），即只有Agg-猪接近对手的行为受输赢影响。QBA和注视行为揭示了不同攻击性猪之间情绪效价的差异：攻击性较低的猪可能更容易受到胜利和失败的情绪影响，但总体而言，攻击性较强的猪在争斗遭遇开始时表达出更多的负面情绪。
